Communication would be more difficult and we would have to use house phones.
it would be horrible because you would not be able to comment on the weather or tell your wife that you love them. the world would be horrible.
One significant effect would be that long range radio communication by shortwave would be impossible.
this is a sign of effective listening.
The median would not change, but the mean would increase.
Humans are evolving creatures. We would either "invent" it again, or create a better, more effective way of communication
Taking language to mean meaningful communication the opposite would be gibberish.
Clarify what you mean by "evolved".
eventually and yourself too. I mean you would have to not eat for months for that to happen. eventually and yourself too. I mean you would have to not eat for months for that to happen.
then we use letter for communication
What do you mean? We already are on Earth.
It is an obselte but modern means of communication